A square sheet of paper is folded along the dotted lines in the direction of the arrows, and holes are then punched through all the layers, as shown in the figures. How will the sheet look when it is opened out?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) →
When a folded sheet is opened, every hole is repeated as its mirror image across each fold line, the last fold being opened first. Here first the lower-right part is folded onto the upper-left part and then the lower-left part is folded onto the upper-right part. Opening the second fold copies the hole across the diagonal fold line (top-left to bottom-right); opening the first fold then copies all of them across the diagonal fold line (top-right to bottom-left). So the opened sheet has 4 holes, placed symmetrically about the fold lines.
Option (2) — Incorrect. It has an extra hole: the opened sheet has 4 holes, this option shows 5 holes.
Option (3) — Incorrect. The copies across the diagonal fold line (top-left to bottom-right) (the second fold) are missing, so it shows only 2 holes.
Option (4) — Incorrect. Only the second fold has been opened: the copies across the diagonal fold line (top-right to bottom-left) are missing, so it shows only 2 holes.